Liquid Crystal Display Device

ABSTRACT

A height difference under a sealant is reduced in a case where lines are present under the sealant. 
     There is provided a substrate having an active matrix display circuit and peripheral driving circuits, a counter substrate having a counter electrode provided on the substrate in a face-to-face relationship therewith, a sealant provided between the substrate and the counter substrate such that it surrounds the active matrix display circuit and peripheral driving circuits, a liquid crystal material provided inside the sealant, a plurality of external connection lines provided on the substrate under the sealant with a resin inter-layer film interposed therebetween for electrically connecting the active matrix display circuit and peripheral driving circuits to circuits present outside the sealant and an adjustment layer provided in the same layer as the plurality of external connection lines.

The present invention relates to a structure of a liquid crystal displaydevice integral with peripheral circuits in which an active matrixdisplay circuit and peripheral driving circuits are provided on the samesubstrate.

More particularly, the present invention relates to a configuration inwhich peripheral driving circuits are provide inside a region enclosedby a sealant for sealing a liquid crystal material.

There are configurations of liquid crystal display devices integral withperipheral circuits having an active matrix circuit and peripheraldriving circuits provided on the same substrate in which peripheraldriving circuits are provided inside a region enclosed by a sealant forsealing the liquid crystal material. A CPU, a memory, a control circuitand the like may be provided in addition to peripheral driving circuits.

In such a device, lines are provided under the region where the sealantis provided (hereinafter referred to as “sealant region”). For example,such lines include external connection lines for transmitting signalsbetween the outside and inside of the sealant and short rings formed byextending scanning lines and signal lines and shorting them outside thesealant region in order to prevent electrostatic breakdown of TFTs (thinfilm transistors) forming an active matrix display circuit atmanufacturing steps.

The lines provided under the sealant region results in different heightsin the sealant. Such a height difference is, primarily caused by tworeasons.

One reason is that the lines under the sealant region are localized andare not present in some locations.

The other reason is that the line width and line intervals of the linesunder the sealant region vary.

FIG. 13 shows an example of a liquid crystal display device integralwith peripheral driving circuits. Referring to FIG. 13, a substrate 1501and a counter substrate 1502 are disposed in a face-to-face relationshipwith a sealant 1505 having an injection hole 1510 interposedtherebetween to form a panel. On the substrate 1501, there is providedan active matrix display circuit 1503, peripheral driving circuits suchas shift registers and decoders for driving the circuit 1503 andexternal connection lines 1508 for electrically connecting thosecircuits and circuits outside the sealant to transmit signalstherebetween.

The external connection lines 1508 are connected to the externalcircuits through an FPC (flexible printed circuit).

There is further provided short rings 1509 which are formed by extendingscanning lines and signal lines. The short rings 1509 are formed toshort those lines with each other outside the sealant region to preventelectrostatic breakdown of TFTs (thin film transistors) forming theactive matrix display circuit at manufacturing steps. The configurationof the short rings 1509 shown in FIG. 13 is a configuration formulti-shot manufacture in which a plurality of panels are obtained froma single substrate. Although not shown in FIG. 13, the short rings areelectrically connected to the short rings of an adjacent panel to shortthe scanning lines and signal lines, and the short rings are separatedwhen the substrate is separated into independent panels as shown in FIG.13.

FIG. 14A shows sections of a region under the sealant 1505 where theexternal connection lines 1508 are provided and a region where no lineis provided. Referring to FIG. 14A, provided on the substrate 1501 arean underlying film 1511 such as a silicon oxide film, a firstinter-layer film 1512 formed by a silicon oxide film, a silicon nitridefilm or a multi-layer film consisting of them, external connection lines1508 and a resin inter-layer film 1513 made of resin such as polyimideor acrylic.

The external connection lines 1508 are formed by a metal film, e.g., analuminum film, in the range from about 200 nm to 700 nm. Althoughdependent on the application, the external connection lines 1508 areformed by a plurality of lines each having a width in the range from 50μm to 300 μm provided as a group at intervals in the range from 30 μm to100 μm.

In such a configuration, the resin inter-layer film 1513 has a thicknessof about 1 μm and is provided in order to achieve flatness. However,regions of the resin inter-layer film 1513 having the externalconnection lines 1508 is higher than regions having no line by a heightdifference d. Such a step can be in the range from a few hundred nm to500 nm, although it is smaller than the height (thickness) of theexternal connection lines 1508.

FIG. 14B shows a sectional view of a region under the sealant 1505 wherethe short rings 1509 are provided in the same layer and using the samematerial as those of the external connection lines 1508. Therefore, thethickness (height) of the short rings 1509 is the same as that of theexternal connection lines 1508. The short rings are extensions of signallines and scanning lines. They are a plurality of lines each having awidth in the range from 2 μm to 10 μm provided as a group at intervalsin the range from 20 μm to 100 μm.

There is a height difference d2 between the region where the short rings1509 are provided and the region where the external connection lines1508 are provided. This height difference can be also in an approximaterange from a few hundred nm to 500 nm. Especially, the height differenceis increased when a plurality of the resin inter-layer films are formed.A step on the order of 1000 nm may be formed when the films are stackedto a thickness on the order of 2 μm.

A step can be formed on the resin inter-layer film also between theregion having the short rings 1509 and the region having no line.

The substrate having the active matrix display circuit provided thereonand the counter circuit are provided in a face-to-face relationship witha sealant including spacers (spherical or cylindrical microscopicparticles for maintaining an interval between the substrates) interposedtherebetween. Therefore, any uneven height difference in the sealantregion where the sealant is provided causes distortion of the countersubstrate such as flexing and twisting to make the substrate intervaluneven. As a result, a uniform state of display can not be achieved in asingle screen and there will be unevenness in color and brightness.

The problem of the distortion of the substrate does not occur even inthe presence of a height difference under the sealant region if theheight difference is uniformly distributed under the sealant region.However, since the lines extending across the sealant region areprovided as a group of lines which are locally concentrated, in general,such a height difference is not uniformly distributed under the sealantregion. This results in distortion of the substrate as described above.

The allowance (the range in which no uneven display occurs) for theheight difference under the sealant region is on the order of only 1000nm for a TN (twisted nematic) type liquid crystal display. Especially,for an ECB (electrically controlled multi-reflectivity) mode utilizingnematic liquid crystal, a height difference of only 200 nm causesdistortion of the substrate which leads to uneven display and colorvariation. For example, a height difference of 200 nm between theexternal connection lines and the short rings makes the substrateinterval in the vicinity of the short rings smaller than that in thevicinity of the external connection lines, thereby causing distortion ofthe substrate and uneven display. Therefore, it is quite important for aliquid crystal display device to have a small height difference underthe sealant region in order to provide uniform display in one screen.

It is an object of the present invention to reduce a height differenceunder a sealant region where wiring is provided under the sealant region(sealant).

Especially, it is an object of the present invention to reduce a heightdifference under a sealant region in a configuration wherein wiring isprovided under the sealant region and one or more inter-layer films madeof a resin material are provided on the wiring.

It is another object of the present invention to reduce a heightdifference under the sealant region in a configuration wherein lineshaving different widths are provided under the sealant region andwherein one or more inter-layer films made of a resin material areprovided above those lines.

According to the present invention, a liquid crystal display devicecomprises:

a first substrate having a active matrix circuit and peripheral drivingcircuits provided thereon;

a counter substrate having a counter electrode provided in aface-to-face relationship with the substrate;

a sealant provided between the first substrate and the counter substratesuch that it surrounds the active matrix circuit and peripheral drivingcircuits;

a liquid crystal material provided inside the sealant;

a plurality of external connection lines provided on the first substrateunder the sealant with a resin inter-layer film interposed therebetweenfor electrically connecting the active matrix display circuit andperipheral driving circuits to circuits present outside the sealant; and

an adjustment layer provided in the same layer as the plurality ofexternal connection lines.

In the above-described configuration, the adjustment layer may beprovided with the same thickness as that of the plurality of externalconnection lines.

In either of the above-described configurations, the adjustment layermay be provided with the same intervals and width as those of theplurality of external connection lines.

In any of the above-described configurations, at least one of theplurality of external connection lines may be electrically connected inparallel to one of a plurality of auxiliary lines provided in a layerdifferent from that of the external connection lines to reduceelectrical resistance, and an adjustment layer may be provided in thesame layer as the auxiliary lines.

A plurality of lines extending across the sealant thereunder and havinga smaller width than that of each of the plurality of externalconnection lines and intervals greater than the width may be provided ina layer different from that of the plurality of external connectionlines, and the plurality of lines may include extensions from scanninglines and signal lines that form the active matrix display circuit.

Further, a plurality of lines extending across the sealant thereunderand having a smaller width than that of each of the plurality ofexternal connection lines and intervals greater than the width may beprovided in the same layer as that of the plurality of externalconnection lines, and the plurality of lines may include extensions fromscanning lines and signal lines that form the active matrix displaycircuit. The plurality of lines may include a portion under the sealantwhere the width is increased.

In the configuration in which at least one of the plurality of externalconnection lines is electrically connected in parallel to one of aplurality of auxiliary lines provided in a layer different from that ofthe plurality of external connection lines to reduce electricalresistance and in which an adjustment layer is provided in the samelayer as the auxiliary lines:

a plurality of first lines having a width smaller than that of each ofthe plurality of auxiliary lines may be provided at intervals greaterthan the width in the same layer as the auxiliary lines such that theyextend across the sealant thereunder;

the plurality of first lines may include extensions of either thescanning lines or signal lines forming the active matrix displaycircuit;

the plurality of first lines have a portion under the sealant where thewidth thereof is increased;

a plurality of second lines having a width smaller than that of each ofthe plurality of auxiliary lines may be provided at intervals greaterthan the width in the same layer as the auxiliary lines such that theyextend across the sealant thereunder;

the plurality of second lines may include extensions of the other ofgroup of lines, i.e., the scanning lines or signal lines forming theactive matrix display circuit; and

the plurality of second lines have a portion under the sealant where thewidth thereof is increased.

In the above-described configuration, the extensions of either thescanning lines or signal lines forming the active matrix circuit may beprovided in a face-to-face relationship with the adjustment layerprovided in a layer different from that of either the scanning lines orsignal lines.

Further, the adjustment layer may have a region under the sealant in aface-to-face relationship with the extension of either the scanninglines or signal lines, which is electrically separated from adjacentregions.

Furthermore, the adjustment layer may be electrically divided into aplurality of segments in the region in a face-to-face relationship withthe extensions of either the scanning lines or signal lines.

The extensions of the other group of lines, i.e., either the scanninglines or signal lines forming the active matrix display circuit may beprovided in a face-to-face relationship with an adjustment layerprovided in a layer different from that of the other group of lines,i.e., the scanning lines or signal lines.

In addition, the adjustment layer may have a region facing the extensionof either the scanning lines or signal lines, which is electricallyseparated from adjacent regions.

Moreover, the adjustment layer may be electrically divided into aplurality of segments in the region facing the extensions of either thescanning lines or signal lines.

According to the principle of the present invention, regions under asealant are adjusted to a height similar to that of the highest regionunder the sealant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a configuration of an embodiment of the present invention.

FIGS. 2A and 2B show the configuration of the embodiment of the presentinvention.

FIGS. 3A and 3B show a configuration of another embodiment of thepresent invention.

FIGS. 4A and 4B show a configuration of still another embodiment of thepresent invention.

FIG. 5 shows a configuration of still another embodiment of the presentinvention.

FIGS. 6A and 6B show the configuration of the embodiment of the presentinvention.

FIGS. 7A and 7B show the configuration of the embodiment of the presentinvention.

FIGS. 8A and 8B show the configuration of the embodiment of the presentinvention.

FIGS. 9A and 9B show a configuration of still another embodiment of thepresent invention.

FIGS. 10A and 10B show a configuration of still another embodiment ofthe present invention.

FIGS. 11A and 11B show a configuration of still another embodiment ofthe present invention.

FIG. 12 shows a configuration of still another embodiment of the presentinvention.

FIG. 13 shows a configuration of an example of a liquid crystal panel.

FIGS. 14A and 14B show the cross section of the liquid crystal panel ofFIG. 13.

FIGS. 15A through 15F show examples of the application of the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be describedwith reference to the accompanying drawings.

Example 1

The present embodiment refers to an example of flattening of a sealantregion to eliminate a height difference in a configuration whereinexternal connection lines are provided under the sealant region.

FIG. 1 shows a configuration of an active matrix display circuitaccording to the present embodiment.

Referring to FIG. 1, a substrate 101 and a counter substrate 102 aredisposed in a face-to-face relationship with a sealant 105 having aninjection hole 110 interposed therebetween to form a panel. Provided onthe substrate 101 are an active matrix display circuit 103, peripheraldriving circuits 104 such as shift registers and decoders for drivingthe circuit 103 and external connection lines 108 for electricallyconnecting those circuits to circuits (not shown) outside the sealant totransmit signals therebetween. The external connection lines 108 areconnected to the external circuits through an FPC (flexible printedcircuit). Both of the active matrix circuit and the driving circuit maybe formed on the substrate using thin film transistors as disclosed by apending application Ser. No. 08/879,583 (filed on Jun. 20, 1997) forexample. The entire disclosure of the application Ser. No. 08/879,583 isincorporated herein by reference.

Referring again to FIG. 1, the peripheral driving circuits 104 have aredundant configuration wherein two driving circuits are provided foreach of signal lines and scanning lines.

In FIG. 1, there is provided an adjustment layer 106 which extends alongthe sealant 105 in continuation to the region under the sealant 105 withan inter-layer film (not shown) interposed in the same layer as that ofthe external connection lines but in a region where the externalconnection lines 108 are not present.

FIG. 2A shows an enlarged view of the region A 109 in FIG. 1, and FIG.2B shows a sectional view taken along the line A-A′ in FIG. 2A.

Referring to FIG. 2A, a plurality of external connection lines 108having a predetermined width w1 are provided in a concentrated group atpredetermined intervals w2. According to the present embodiment, thewidth w1 is in the range from 50 μm to 300 μm and is 200 μm for example.The intervals w2 are in the range from 30 μm to 100 μm and is 50 μmhere.

Referring to FIG. 2B, a first inter-layer film 112 and a resininter-layer film 113 are provided on the substrate 101 made of glass,quartz, silicon wafer or the like with an underlying film 111constituted by a silicon oxide film or the like interposed therebetween,and a sealant 105 is provided thereon. An orientation film (not shown)may be provided between the sealant 105 and the resin inter-layer film113.

As apparent from FIG. 2B, the external connection lines 108 and anadjustment layer 106 are formed between the first inter-layer film 112and resin inter-layer film 113 in the same layer and using the samematerial such as aluminum. Therefore, the adjustment layer 106 has thesame thickness (height) as the external connection lines 108 such thatregions under the inter-layer film 113 where the external connectionlines 108 are not present have the same height as the externalconnection lines 108.

Such a configuration reduces the difference in height between a regionhaving the external connection lines 108 and a region having no externalconnection line on the upper surface of the resin inter-layer film 113under the region where the sealant 105 is provided. This also reducesdistortion of the counter substrate when it is put together. Further,uniform display without variation can be achieved in one screen.

While the adjustment layer 106 has a configuration like a continuouslines, the external connection lines have intervals w2. As a result, aheight difference can occur because the region including the externalconnection lines 108 in the region under the sealant 105 is slightlylower than the region where the adjustment layer 106 is provided.However, since the width w1 of the external connection lines 108 issufficiently greater than the intervals w1 between the lines, such aheight difference is quite small and does not cause uneven display.

The external connection lines 108 and the adjustment layer 106 may beprovided in a layer different from that of the signal lines (sourcelines) of the TFTs forming the active matrix display circuit andperipheral driving circuits, although they are in the same layer in theconfiguration of the present embodiment.

The external connection lines 108 and adjustment layer 106 may beprovided in different layers with the same thickness, which is stillsimilarly effective as providing them in the same layer. For example,the adjustment layer 106 may be provided under the first inter-layerfilm 112, and the external connection lines 108 may be provided abovethe first inter-layer film 112. Alternatively, their positions may bereversed. When the external connection lines 108 and adjustment layer106 are provided in the same layer, it is easier to predict and controlthe height difference under the sealant region at a designing phase.

The first inter-layer film 112 may be a silicon oxide film, a siliconnitride film or a multi-layer film which is a combination thereof. Theresin inter-layer film 113 is made of organic resin such as acrylic orpolyimide and is formed through deposition using a spin coating processor the like.

When the adjustment layer 106 is fabricated at a step different fromthose for other lines in the same layer, more fine adjustment of aheight difference can be carried out, though the number of stepsincreases.

While the adjustment layer 106 is provided with a width (the size in thetransverse direction of the sealant) greater than that of the sealant105 along the sealant 105 in the present embodiment; the width may besmaller than that of the sealant 105. Further, it is not essential toprovide the adjustment layer 106 along the sealant 105, and it may beprovided in any position under the region where the sealant is providedas long as the height difference is reduced.

Although the adjustment layer 106 is provided along the sealant 105 inthe region where the injection hole 110 is provided in FIG. 1, it may becontinuous even in the region where the injection hole is provided asindicated by the dotted line 120. A substantially constant electricpotential can be achieved in the plane of the substrate when theadjustment 106 is provided continuously to surround the peripheraldriving circuits 104 and the active matrix display circuit 103 asdescribed above. This is true only when the adjustment layer 106 hasconductivity.

The use of an insulating substrate made of glass, quartz or the like isliable to cause localization of electrostatic charges in the plane ofthe substrate. As a result, electrostatic breakdown of TFTs may becaused by localized electrostatic charges during a rubbing step. Asubstantially constant electric potential can be established in theplane of the substrate by forming the adjustment layer 106 continuouslysuch that it surrounds the peripheral driving circuits 104 and activematrix display circuit 103 to prevent such electrostatic breakdown.

Stripes attributable to the rubbing step sometimes appear on a finishedliquid crystal display. By forming a continuous adjustment layer 106 asdescribed above, such stripes due to rubbing are advantageously reducedon the display, although the reason is unknown.

When the adjustment layer 106 is continuously formed as described above,the position of the injection hole 110 is not limited by the shape ofthe adjustment layer 106, and the hole may be provided in any position.However, the height of the path extending from the injection hole 110 tothe interior of the sealant region may be increased because of thepresence of the adjustment layer 106, resulting in an increase in thetime required for injecting liquid crystal. In other words, the liquidcrystal injection time can be reduced by forming the adjustment layer106 in compliance with the shape of the injection hole 110 as shown inFIG. 1 to make the opening area of the injection hole larger.

While it is not possible to form the adjustment layer 106 such that itcontinuously extend to surround the substrate 101 completely because ofthe presence of the external connection lines 108, it can still providethe effect of establishing a substantially constant electric potentialin the plane of the substrate even if it is not completely continuous. Amore constant electric potential can be achieved by, for example,forming the adjustment layer 106 in the configuration shown in FIGS. 1,2A and 2B and providing conductive lines extending along the peripheryof the substrate to establish a constant electric potential in a layerseparate from the adjustment layer 106, e.g., under the firstinter-layer film 112 shown in FIG. 2B.

While the external connection lines 108 and adjustment layer 106 areprovided under the resin inter-layer film 113, i.e., provided in thelayer above the first inter-layer film 112 in the first embodiment, theymay alternatively be provided under the first inter-layer film 112.

Example 2

The second embodiment refers to another configuration of the adjustmentlayer 106 according to the first embodiment. FIGS. 3A and 3B show theconfiguration of an adjustment layer 301 according to the presentembodiment.

Referring to FIG. 3A, the adjustment layer 301 has the same width w1 asthe external connection lines 108 and is formed in sections at intervalsw2 instead of being formed continuously as the adjustment layer 106 ofthe first embodiment. Specifically, a region having the externalconnection lines 108 and a region having the adjustment layer 301 havethe same structure under the sealant 105.

In such a configuration, the height of the resin inter-layer film 112can be kept substantially equal between the region having the externalconnection lines 108 and the region having the adjustment layer 301.This makes it possible to make the region under the sealant 105 flatterand to therefore achieve a more uniform height compared to theconfiguration according to the first embodiment. Therefore, thedistortion of the counter substrate 102 is minimized to allow preferabledisplay having quite high uniformity in the screen and less variation.

Example 3

The third embodiment refers to an alternative to the configurationdescribed as the first embodiment, in which the resistance of theexternal connection lines is reduced. FIGS. 4A and 4B show aconfiguration according to the third embodiment.

FIG. 4A is a schematic sectional view taken along the line X-X′ in FIG.1 illustrating the application of the configuration of the thirdembodiment to the configuration of the first embodiment.

While the external connection lines are provided between the firstinter-layer film 112 and resin inter-layer film 113 in the firstembodiment, according to the third embodiment, auxiliary lines 401 thatextend along external connection lines 403 are provided under the firstinter-layer film 112 and the external connection lines 403 and auxiliarylines 401 are electrically connected in parallel by forming contactholes in the first inter-layer film 112 to reduce the electricalresistance as shown in FIG. 4A. The auxiliary lines 401 may be formed inother layers to reduce electrical resistance further.

Referring to FIG. 4A, the external connection lines 403 are electricallyconnected to an FPC (flexible printed circuit) 107 through contact holesprovided in the resin inter-layer film 113 through an ITO (indium tinoxide) film 114. In the present embodiment, the ITO film 114 isfabricated at the same step as for an ITO film that forms pixelelectrodes connected to the TFTs of the active matrix display circuit.The ITO film 114 is electrically connected to external circuits throughthe FPC 107.

Among signals applied to the external connection lines 403 from theexternal circuits, clock and video signals have very high frequencies.An active matrix liquid crystal display device has a large area fordisplay, lines forming its circuit inevitably have a length of severalcentimeters or more. However, since the lines themselves have only athickness in the range from a few hundred nm to 700 nm, the lines as awhole have high electric resistance even if a metal such as aluminumhaving high conductivity is used as the line material. A high lineresistance causes delay and deterioration of the propagation of highfrequency signals such as clock and video signals to disallow preferabledisplay.

The configuration described in the present embodiment makes it possibleto reduce electrical resistance of the external connection lines 403significantly to allow an active matrix liquid crystal display integralwith peripheral driving circuits to provide preferable display whendriven at a high frequency and a high speed.

However, in such a configuration wherein a plurality of lines providedin different layers are connected in parallel, a height differencebetween a region under the sealant including the lines and a regionincluding no line will be greater than that in a case where those linesare formed only in one layer.

That is, preferable display can not be achieved due to the increasedheight difference in the region under the sealant, though electricresistance is reduced.

In the configuration according to the present embodiment, an adjustmentlayer having the same thickness (height) as the auxiliary lines 401 isprovided in the same layer as the auxiliary lines 401 provided in orderto reduce electric resistance, and the auxiliary lines 401 and a firstadjustment layer 402 are provided in a layer under the first inter-layerfilm 112. Like the first embodiment, the external connection lines 403and a second adjustment layer 404 are provided above the firstinter-layer film 112, i.e., under the resin inter-layer film 113.

In such a configuration wherein auxiliary lines 401 are provided toreduce electrical resistance, the height difference under the sealantregion can be reduced, and uniform display can be achieved in one screenwithout variation.

In the present embodiment, either or both of the first adjustment layer402 and the second adjustment layer 404 may be configured to have thesame width and intervals as those of the external connection lines 403as shown in the second embodiment. Such a configuration makes itpossible to reduce the height difference under the sealant regionfurther to achieve higher uniformity. In this case, when the auxiliarylines 401 and external connection lines 403 have different widths andintervals, the first adjustment layer 402 and second adjustment layer404 may be formed such that they respectively have the same widths andintervals as the auxiliary lines 401 and external connection lines 403to reduce the height difference under the sealant region for higheruniformity, thereby allowing preferable display.

In the present embodiment, the auxiliary lines and external connectionlines may be replaced with each other to use the lines provided in thelayer under the first inter-layer film as external connection lineswhich establish electrical connection with the FPC.

Example 4

The fourth embodiment refers to a configuration wherein a heightdifference under the sealant region is reduced to achieve a uniformheight in case where lines having different widths and intervals arepresent in the same layer. FIG. 5 shows a configuration of an activematrix liquid crystal display device according to the fourth embodiment.In FIG. 5, reference numbers same as those appear in FIG. 1 indicatelike elements.

Referring to FIG. 5, an active matrix display circuit 103 is differentfrom that shown in FIG. 1 in that one peripheral driving circuit 509such as a shift register or decoder for driving the active matrixdisplay circuit 103 is provided for driving each of the signal lines andscanning lines.

There is provided scanning line short rings 503 which are extensions ofthe scanning lines and signal line short rings 504 which are extensionsof the signal lines on the sides where the peripheral driving circuit509 is not provided. The short rings 503 and 504 are electricallyconnected to each other until the substrate is divided into panels at amulti-shot production step to provide a function of preventing theelectrostatic breakdown of the TFTs forming the active matrix displaycircuit 103 at steps where static electricity can occur such as therubbing step.

Since the short rings 503 and 504 are extensions of the scanning linesand signal lines respectively, the widths and intervals of those lines(a short ring is also described as a line in this specification,although it does not transmit any electric signal in a liquid crystaldisplay device) also the same as those of the scanning lines and signallines. Therefore, the lines have a width in the range from 2 μm to 10 μmand an interval in the range from about 20 μm to about 100 μm which isequal to the pitch of the pixels. Those values obviously changedepending on the application. In general, the scanning line short rings503 and signal line short rings 504 are respectively connected to thegates and sources of the TFTs forming the active matrix display circuit103.

It would be noted here that the line intervals of the short rings 503and 504 are very much larger than the widths of those lines. This isquite contrary to the external connection lines 108.

FIG. 6A shows an enlarged view of the region B 505 in FIG. 5, and FIG.6B shows a section taken along the line B-B′ in FIG. 6A.

FIG. 7A shows an enlarged view of the region C 506 in FIG. 5, and FIG.7B shows a section taken along the line C-C′ in FIG. 7A. FIG. 8A showsan enlarged view of the region D 507 in FIG. 5, and FIG. 8B shows asection taken along the line D-D′ in FIG. 8A.

As shown in FIG. 6A, a plurality of external connection lines 108 havinga predetermined width w1 at predetermined intervals w2 are provided as agroup in a concentrated fashion. The width w1 is in the range from 50 μmto 300 μm, e.g., 200 μm, and the interval w2 is in the range from 30 μmto 100 μm, e.g., 50 μm, in the present embodiment.

As shown in FIG. 6B, a first inter-layer film 112 and a resininter-layer film 113 are provided on a substrate 101 made of glass,quartz, silicon wafer or the like with an underlying film 111constituted by a silicon oxide film or the like interposed therebetween,and a sealant 105 is provided thereon. An orientation film (not shown)may be provided between the sealant 105 and the resin inter-layer film113.

As apparent from FIG. 6B, a first adjustment layer 501 is providedbetween the underlying film 111 and first inter-layer film 112. Thiswill be described later in more detail.

As apparent from FIG. 6B, external connection lines 108 and a secondadjustment layer 502 are formed in the same layer from the samematerial, e.g., aluminum between the first inter-layer film 112 and theresin inter-layer film 113 under the sealant 105.

Therefore, the second adjustment layer 502 has the same thickness(height) as the external connection lines 108 such that a region wherethe external connection lines 108 are not provided under the resininter-layer film 113 has the same height as the external connectionlines 108.

Such a configuration reduces the height difference between the regionhaving the external connection lines 108 and the region having noexternal connection lines on the upper surface of the resin inter-layerfilm 113 under the region where the sealant 105 is provided. As aresult, distortion of the counter substrate is reduced when it is puttogether.

While the second adjustment layer 502 has a configuration that seemslike a continuous line, the external connection lines 108 has theintervals w2. Therefore, the region above the resin inter-layer film 113and under the sealant where the external connection lines 108 areprovided is slightly lower than the region where the second adjustmentlayer 502 is provided, which may cause a height difference. However,since the width w1 of the external connection lines 108 is sufficientlygreater than the interval w2 thereof, the height difference is quitesmall. The present embodiment is similar to the first embodiment up tothis point.

Next, as shown in FIG. 7A which is an enlarged view of the region C 506,the present embodiment includes a signal line short ring 504 provided inthe same layer as the external connection lines 108 and secondadjustment layer 502.

The signal line short ring 504 has a width w3 and an interval w4 ingeneral but has a width w5 greater than the width w3 and an interval w6smaller than the interval w5 in the region under the sealant 105. Thewidth w5 is preferably greater than the interval w6. Preferably, thewidth w5 is as large as possible.

In such a configuration a height difference on the upper surface of theresin inter-layer film 113 in the region under the sealant 105 can bereduced between the region where a plurality of signal short rings 504are provided as a group and the region where the plurality of externalconnection lines 108 are provided as a group.

In other words, in such a configuration, the ratio in a unit area of theregion having the short rings 504 to the region having no short ring inthe region where the plurality of signal short rings 504 are provided asa group under the sealant 105 is made as close as possible to the ratioin the unit area of the region having the external connection lines 108to the region having no external connection line in the region where theplurality of external connection lines 108 are provided as a group.

Next, as shown in FIG. 8A which is an enlarged view of the region D 507and FIG. 8B which is a section taken along the line D-D′ thereof, thefirst adjustment layer 501 is provided in the same layer as the scanningline short rings 503 as has the same thickness (height). The scanningline short rings 503 and the first inter-layer film 501 are formed withthe same width w3 and interval w4. That is, in the present embodiment,the first adjustment layer 501 is the same as the scanning line shortrings 503 except that it has a different line length.

In such a configuration, a height difference on the upper surface of thefirst inter-layer film 112 in the region under the sealant 105 can bereduced between the region having the scanning line short rings 503 andthe region having no scanning line short ring to achieve a uniformheight. That is the formation of the short rings 503 substantiallycauses no problem associated with the height difference on the firstinter-layer film 112 under the sealant 105.

Since the line interval w4 of the scanning line short rings 503 is verymuch greater than the line width w3 thereof, when the first adjustmentlayer 501 has a continuous configuration like that of the adjustmentlayer 106 in the first embodiment, the upper surface of the firstinter-layer film 112 will be higher in the region having the scanningline short rings 503 than in the region having first adjustment layer501.

According to the present embodiment, the fabrication of the secondadjustment layer 502 in a step different from those for other lines inthe same layer will allow finer adjustment of the height difference,although the number of steps will increase.

While the first adjustment layer 501 and second adjustment layer 502 inthe present embodiment are provided along the sealant 105 with a widthgreater than that of the sealant 105 (the size in the transversedirection of the sealant), they may be smaller than the sealant inwidth. Further, it is not essential to provide them along the sealant105, and they may be provided in any position under the region where thesealant is provided as long as the height difference is reduced.

According to the present embodiment, it is advantageous to form thesecond adjustment layer 502 with the same configuration as theadjustment layer 106 in the second embodiment instead of a continuousconfiguration to reduce the height difference further.

According to the present embodiment, when the external connection lines108 are provided in the same layer as the first adjustment layer 501 andthe scanning line short rings 503, the relevant widths and intervals ofthe adjustment layer and short rings may be changed to those in thepresent embodiment.

Example 5

The fifth embodiment shows an example wherein the configuration shown inthe fourth embodiment is modified to a configuration with reducedresistance of the external connection lines 403 as shown in the thirdembodiment. The present embodiment employs the same configurations ofthe external connection lines 403 and auxiliary lines 401 as those inthe third embodiment.

FIGS. 9A and 9B are an enlarged view and a section taken along the lineD-D′ of the region D 507 in FIG. 5, respectively, according to thepresent embodiment. The present embodiment is different from the fourthembodiment in that, as shown in FIGS. 9A and 9B, the scanning line shortrings 503 under the first inter-layer film 112 have an increased widthand decreased intervals in the region under the sealant like the signalline short rings 504 shown in FIGS. 7A and 7B according to the fourthembodiment (The sealant 105 is as shown in the drawings described so faralthough not shown in FIG. 9A).

The reason for the above-described configuration—is that a heightdifference on the upper surface of the resin inter-layer film 113 in theregion under the sealant 105 can be reduced between the region where aplurality of scanning line short rings 503 are provided as a group andthe region where a plurality of auxiliary lines 401 for the externalconnection lines 403 are provided as a group.

Example 6

The sixth embodiment shows a configuration wherein capacitance betweenshort rings and an adjustment layer is reduced in a region where theyface each other.

FIGS. 10A and 10B are an enlarged view and a sectional view taken alongthe line D-D′ of the region D 507 in FIG. 5 according to the presentembodiment.

In FIG. 9A associated with the fifth embodiment, the second adjustmentlayer 502 faces the scanning line short rings 503 in electrical andphysical continuity thereto. The first inter-layer film 112 is presentbetween them. Since the first inter-layer film 112 is an insulating filmconstituted by a silicon oxide film, a silicon nitride film or amulti-layer film consisting thereof, capacitance is formed between thescanning line short rings 503 and the second adjustment layer 502because the second adjustment layer 502 is a conductor. However, sincethe scanning line short rings 503 are extensions of the scanning linesof the active matrix display circuit 103, the presence of theabove-described capacitance increases the load required to drive thescanning lines, adversely affecting the display.

In order to solve such a problem, according to the present embodiment,the second adjustment layer 502 is divided into independent segments inelectrical isolation from each other in positions where they facerespective scanning line short rings 503 as shown in FIGS. 10A and 10B.Specifically, the second adjustment layer 502 is divided into segmentshaving substantially the same configuration as the scanning line shortrings 503 in positions where they face the respective scanning lineshort rings 503. As a result, the capacitance can be reduced withoutincreasing the height difference under the sealant.

Such a configuration can be applied to the first adjustment layer 501facing the signal line short rings 504 to achieve the same effect.

Further, such a configuration may be applied to the configurationaccording to the fourth embodiment where the width of the scanning lineshort rings 503 is not increased, though the effect is somewhat reduced.

Example 7

The seventh embodiment is an alternative to the configuration accordingto the sixth embodiment. A configuration according to the seventhembodiment is shown in FIGS. 11A and 11B. In the present embodiment, ascanning line short ring 503 is shaped such that its area varies in thetransverse direction of the sealant. Such a configuration is alsoeffective in reducing capacitance without increasing the heightdifference under the sealant.

Such a configuration may be applied to the first adjustment layer 501that faces the signal line short rings 504 to achieve the same effect.

Example 8

The eighth embodiment shows an alternative to the configurationsaccording to the sixth and seventh embodiments. A configurationaccording to the eighth embodiment is shown in FIG. 12.

Although the configurations according to the sixth and seven embodimentsare effective in reducing capacitance, when one scanning line short ring503 is shorted with the second adjustment layer 502 by a spacer or thelike which penetrates through the resin inter-layer film because of apressure applied thereto, the short ring will have capacitance which isdifferent in magnitude from those of other scanning line short rings. Asa result, shorted line will have a driving load different from those ofother scanning lines and have different display characteristics.

According to the eighth embodiment, a region of the second adjustmentlayer 502 that faces one scanning line short ring 503 is further dividedinto a plurality of segments. As a result, even when one of theplurality of divided second adjustment layers 502 facing one scanningline short ring 503 is shorted, the second adjustment layers 502 are notshorted as a whole, and the difference is capacity from those of otherscanning line short rings 503 can be suppressed to suppress variationsand differences in display characteristics.

Example 9

The present embodiment refers to products utilizing active matrix liquidcrystal display devices as described in the above embodiments.Electronic apparatuses that may embody the invention include videocameras, still cameras, projectors, head mount displays, car navigationsystems, personal computers, personal digital assistants (mobilecomputers and cellular mobile phones) and the like. FIGS. 15A through15F are schematic external views of electronic apparatuses according tothe present embodiment.

FIG. 15A shows a mobile computer which is constituted by a main body2001, a camera portion 2002, an image-receiving portion 2003, operationswitches 2004 and a liquid crystal display device 2005.

FIG. 15B shows a head mount display which is constituted by a main body2101, a pair of liquid crystal display devices 2102 and a band portion2103 for securing the main body on the head of a person. The pair ofliquid crystal display devices display images for the left and righteyes, respectively. The user gets visual perception of the imagesthrough an optical system. Then, the user get visual perception whichseems like a large screen spreading in front of his or her eyes.

FIG. 15C shows a cellular mobile phone which is constituted by a mainbody 2201, a speech output portion 2202, a speech input portion 2202, aliquid crystal display device 2204, operation switches 2205 and anantenna 2206.

FIG. 15D shows a video camera which is constituted by a main body 2301,a reflection type liquid crystal display device 2302, a speech inputportion 2303, operation switches 2304, a battery 2305 and animage-receiving portion 2306.

FIG. 15E shows a rear type projector in which light emitted by a lightsource 2402 provided in a main body 2401 is reflected and modulated by apixel portion in a reflection type liquid crystal display device 2403.The reflected light is projected through a mirror 2404 and 2405 upon ascreen 2406 to be displayed thereon as an image.

FIG. 15F shows a front type projector in which light emitted by a lightsource 2502 in a main body 2501 is modulated and transmitted by atransmission type liquid crystal display device 2503. The transmittedlight is projected by an optical system 2504 upon a screen 2505 todisplay an image thereon.

The invention disclosed in this specification makes it possible toreduce a height difference in a sealant region when lines are presentunder the sealant region, thereby allowing distortion of a countersubstrate to be eliminated and allowing a liquid crystal display devicehaving excellent uniformity of display in a screen to be provided.

What is claimed is:
 1. (canceled)
 2. A liquid crystal display devicecomprising: a substrate; thin film transistors over the substrate; pixelelectrodes each electrically connected to one of the thin filmtransistors; a counter substrate facing the substrate; a liquid crystalmaterial provided between the substrate and the counter substrate; asealant provided between the substrate and the counter substrate; afirst conductive line over the substrate; a first insulating film overthe first conductive line; a second conductive line over the firstinsulating film; a second insulating film over the second conductiveline; a transparent conductive film over the second insulating film; anda flexible printed circuit over the transparent conductive film; whereinthe sealant is in direct contact with the second insulating film;wherein the sealant overlaps the first conductive line and the secondconductive line; wherein the second conductive line overlaps the firstconductive line; wherein the sealant does not overlap the transparentconductive film; wherein the first conductive line is electricallyconnected to the second conductive line; wherein the second conductiveline is electrically connected to the flexible printed circuit via thetransparent conductive film; wherein the second conductive line and thetransparent conductive film are in direct contact via an opening in thesecond insulating film; wherein the flexible printed circuit and thetransparent conductive film each completely cover the opening; andwherein the transparent conductive film is made from a same layer as thepixel electrodes.
 3. A liquid crystal display device according to claim2, wherein the second insulating film comprises resin.
 4. A liquidcrystal display device according to claim 2, wherein the firstconductive line and the second conductive line are configured totransmit a high frequency signal.
 5. A liquid crystal display deviceaccording to claim 2, wherein the first conductive line is in directcontact with the second conductive line.
 6. A liquid crystal displaydevice according to claim 2, wherein a peripheral driving circuit isformed over the substrate.
 7. A liquid crystal display devicecomprising: a substrate; thin film transistors over the substrate; pixelelectrodes each electrically connected to one of the thin filmtransistors; a counter substrate facing the substrate; a liquid crystalmaterial provided between the substrate and the counter substrate; asealant provided between the substrate and the counter substrate; afirst conductive line over the substrate; a first insulating film overthe first conductive line; a second conductive line over the firstinsulating film; a second insulating film over the second conductiveline; a transparent conductive film over the second insulating film; anda flexible printed circuit over the transparent conductive film; whereinthe sealant is in direct contact with the second insulating film;wherein the second conductive line overlaps the first conductive lineunder the sealant; wherein the sealant does not overlap the transparentconductive film; wherein the first conductive line is electricallyconnected to the second conductive line; wherein the second conductiveline is electrically connected to the flexible printed circuit via thetransparent conductive film; wherein the second conductive line and thetransparent conductive film are in direct contact via an opening in thesecond insulating film; wherein the flexible printed circuit and thetransparent conductive film each completely cover the opening; andwherein the transparent conductive film is made from a same layer as thepixel electrodes.
 8. A liquid crystal display device according to claim7, wherein the second insulating film comprises resin.
 9. A liquidcrystal display device according to claim 7, wherein the firstconductive line and the second conductive line are configured totransmit a high frequency signal.
 10. A liquid crystal display deviceaccording to claim 7, wherein the first conductive line is in directcontact with the second conductive line.
 11. A liquid crystal displaydevice according to claim 7, wherein a peripheral driving circuit isformed over the substrate.
 12. A liquid crystal display devicecomprising: a substrate; thin film transistors over the substrate; pixelelectrodes each electrically connected to one of the thin filmtransistors; a counter substrate facing the substrate; a liquid crystalmaterial provided between the substrate and the counter substrate; asealant provided between the substrate and the counter substrate; afirst conductive line over the substrate; a first insulating film overthe first conductive line; a second conductive line over the firstinsulating film; a second insulating film over the second conductiveline; a transparent conductive film over the second insulating film; aflexible printed circuit over the transparent conductive film; and aconductive layer over the substrate; wherein the sealant is in directcontact with the second insulating film; wherein the sealant overlapsthe first conductive line and the second conductive line; wherein thesecond conductive line overlaps the first conductive line; wherein thesealant does not overlap the transparent conductive film; wherein thefirst conductive line is electrically connected to the second conductiveline; wherein the second conductive line is electrically connected tothe flexible printed circuit via the transparent conductive film;wherein the second conductive line and the transparent conductive filmare in direct contact via an opening in the second insulating film;wherein the flexible printed circuit and the transparent conductive filmeach completely cover the opening; wherein the transparent conductivefilm is made from a same layer as the pixel electrodes; wherein thesealant overlaps the conductive layer; and wherein the conductive layeris not electrically connected to any of the first conductive line, thesecond conductive line, the thin film transistors, and the flexibleprinted circuit.
 13. A liquid crystal display device according to claim12, wherein the second insulating film comprises resin.
 14. A liquidcrystal display device according to claim 12, wherein the firstconductive line and the second conductive line are configured totransmit a high frequency signal.
 15. A liquid crystal display deviceaccording to claim 12, wherein the first conductive line is in directcontact with the second conductive line.
 16. A liquid crystal displaydevice according to claim 12, wherein a peripheral driving circuit isformed over the substrate.
 17. A liquid crystal display devicecomprising: a substrate; thin film transistors over the substrate; pixelelectrodes each electrically connected to one of the thin filmtransistors; a counter substrate facing the substrate; a liquid crystalmaterial provided between the substrate and the counter substrate; asealant provided between the substrate and the counter substrate; afirst conductive line over the substrate; a first insulating film overthe first conductive line; a second conductive line over the firstinsulating film; a second insulating film over the second conductiveline; a transparent conductive film over the second insulating film; aflexible printed circuit over the transparent conductive film; and aconductive layer over the substrate; wherein the sealant is in directcontact with the second insulating film; wherein the second conductiveline overlaps the first conductive line under the sealant; wherein thesealant does not overlap the transparent conductive film; wherein thefirst conductive line is electrically connected to the second conductiveline; wherein the second conductive line is electrically connected tothe flexible printed circuit via the transparent conductive film;wherein the second conductive line and the transparent conductive filmare in direct contact via an opening in the second insulating film;wherein the flexible printed circuit and the transparent conductive filmeach completely cover the opening; wherein the transparent conductivefilm is made from a same layer as the pixel electrodes; wherein thesealant overlaps the conductive layer; and wherein the conductive layeris not electrically connected to any of the first conductive line, thesecond conductive line, the thin film transistors, and the flexibleprinted circuit.
 18. A liquid crystal display device according to claim17, wherein the second insulating film comprises resin.
 19. A liquidcrystal display device according to claim 17, wherein the firstconductive line and the second conductive line are configured totransmit a high frequency signal.
 20. A liquid crystal display deviceaccording to claim 17, wherein the first conductive line is in directcontact with the second conductive line.
 21. A liquid crystal displaydevice according to claim 17, wherein a peripheral driving circuit isformed over the substrate.
 22. A liquid crystal display devicecomprising: a substrate; thin film transistors over the substrate; pixelelectrodes each electrically connected to one of the thin filmtransistors; a counter substrate facing the substrate; a liquid crystalmaterial provided between the substrate and the counter substrate; asealant provided between the substrate and the counter substrate; afirst conductive line over the substrate; a first insulating film overthe first conductive line; a second conductive line over the firstinsulating film; a second insulating film over the second conductiveline; a transparent conductive film over the second insulating film; aflexible printed circuit over the transparent conductive film; a firstconductive layer formed from a same layer as the first conductive line;and a second conductive layer formed from a same layer as the secondconductive line; wherein the sealant is in direct contact with thesecond insulating film; wherein the sealant overlaps the firstconductive line and the second conductive line; wherein the secondconductive line overlaps the first conductive line; wherein the sealantdoes not overlap the transparent conductive film; wherein the firstconductive line is electrically connected to the second conductive line;wherein the second conductive line is electrically connected to theflexible printed circuit via the transparent conductive film; whereinthe second conductive line and the transparent conductive film are indirect contact via an opening in the second insulating film; wherein theflexible printed circuit and the transparent conductive film eachcompletely cover the opening; wherein the transparent conductive film ismade from a same layer as the pixel electrodes; wherein the secondconductive layer overlaps the first conductive layer under the sealant;and wherein the first conductive layer and the second conductive layerare not electrically connected to any of the first conductive line, thesecond conductive line, the thin film transistors, and the flexibleprinted circuit.
 23. A liquid crystal display device according to claim22, wherein the second insulating film comprises resin.
 24. A liquidcrystal display device according to claim 22, wherein the firstconductive line and the second conductive line are configured totransmit a high frequency signal.
 25. A liquid crystal display deviceaccording to claim 22, wherein the first conductive line is in directcontact with the second conductive line.
 26. A liquid crystal displaydevice according to claim 22, wherein a peripheral driving circuit isformed over the substrate.
 27. A liquid crystal display devicecomprising: a substrate; thin film transistors over the substrate; pixelelectrodes each electrically connected to one of the thin filmtransistors; a counter substrate facing the substrate; a liquid crystalmaterial provided between the substrate and the counter substrate; asealant provided between the substrate and the counter substrate; afirst conductive line over the substrate; a first insulating film overthe first conductive line; a second conductive line over the firstinsulating film; a second insulating film over the second conductiveline; a transparent conductive film over the second insulating film; aflexible printed circuit over the transparent conductive film; a firstconductive layer formed from a same layer as the first conductive line;and a second conductive layer formed from a same layer as the secondconductive line; wherein the sealant is in direct contact with thesecond insulating film; wherein the second conductive line overlaps thefirst conductive line under the sealant; wherein the sealant does notoverlap the transparent conductive film; wherein the first conductiveline is electrically connected to the second conductive line; whereinthe second conductive line is electrically connected to the flexibleprinted circuit via the transparent conductive film; wherein the secondconductive line and the transparent conductive film are in directcontact via an opening in the second insulating film; wherein theflexible printed circuit and the transparent conductive film eachcompletely cover the opening; wherein the transparent conductive film ismade from a same layer as the pixel electrodes; wherein the secondconductive layer overlaps the first conductive layer under the sealant;and wherein the first conductive layer and the second conductive layerare not electrically connected to any of the first conductive line, thesecond conductive line, the thin film transistors, and the flexibleprinted circuit.
 28. A liquid crystal display device according to claim27, wherein the second insulating film comprises resin.
 29. A liquidcrystal display device according to claim 27, wherein the firstconductive line and the second conductive line are configured totransmit a high frequency signal.
 30. A liquid crystal display deviceaccording to claim 27, wherein the first conductive line is in directcontact with the second conductive line.
 31. A liquid crystal displaydevice according to claim 27, wherein a peripheral driving circuit isformed over the substrate.